1. Field of the Invention
This invention relates generally to devices for preventing undesired objects from passing between a toilet bowl fixture and a waste line system. More particularly, this invention relates to devices for preventing rats, snakes and other animals from emerging from a waste line system into a toilet bowl.
2. Prior Art
A conventional toilet bowl fixture designed for a floor mount installation includes an annular discharge flange at the base thereof. A wax ring mounted between the discharge flange of the toilet bowl fixture and the sewer line functions to seal the toilet against leakage between the discharge flange and the sewer line.
Various devices have been disclosed in the prior art for preventing foreign objects such as sanitary napkins and disposable diapers from being flushed from a toilet bowl fixture into a waste line system. Such devices are intended to prevent flushing of such foreign objects into a sewer line while at the same time avoiding interference with the passage of water, toilet paper and human waste into the line.
Halstad, U.S. Pat. No. 4,307,476, disclosed an expansible ring made of non-ferrous wire or the like, having at circumferentially-spaced points a series of hook-like members made of wire that extend radially of the ring. Each of the members included a straight portion extending radially outwardly, a downwardly-extending portion extending perpendicularly to the straight portion, an inwardly extending portion, and a terminal portion extending angularly with respect to the inwardly extending portion and terminating in a point. In use, the device was embedded in a wax ring underlying the discharge flange of a floor-mounted toilet bowl fixture. The sharp point of the hooks shred toilet tissue and also acted as hooks to catch undesirable material and prevent it from entering sewer lines. A disadvantage of Halstad's device is that it would not prevent the movement of solid objects, such as a can, container, or a small live animal, between a sewer line and an attached toilet bowl fixture.
Harrington, U.S. Pat. No. 4,555,818, disclosed a waste line trap for placement within a discharge conduit of a toilet bowl fixture comprising a cylinder and a plurality of inwardly extending fins having flat side walls and downwardly beveled top surfaces. Although Harrington's trap prevented the discharge into a sewer line of solid objects such as cans and containers while simultaneously permitting normal flushing of a toilet bowl fixture, it did not provide an adequate barrier to prevent movement of small animals from a sewer line into a toilet bowl fixture.
Mathey, U. S. Pat. No. 2,281,448, disclosed a device for partially obstructing a pipe, intended, for example, to be inserted in the fill pipe of a gasoline tank, which would permit entrance of gasoline into the tank while at the same time prohibiting the admission of a siphon tube into the tank. Mathey's device comprised a plurality of rodlike members, which may be of relatively stiff and strong wire, the ends of which were collected and secured. The wires were of two different lengths and arranged in a generally conical formation such that the bases of the two cones thus formed were of greater diameter than the inside diameter of the pipe with which the device was to be used. The base ends of the longer wires were bent outwardly to form hooklike portions while the base ends of the shorter wires were straight. In use, the apex portion of the device was first inserted into a pipe with the conical bases retracted; the device was then further inserted into the pipe and the compressed wires were permitted to spring radially outward, thereby locking the device in place. Mathey's device is wholly unsuited to repel live animals attempting to enter a toilet bowl fixture from a sewer line, however, because regardless of where it is positioned or how it is oriented it would interfere with the normal flushing of the toilet.
Thus, there remains a need for a device that is capable of repelling the movement of small live animals from a sewer line into a toilet bowl fixture without interfering with the normal flushing of the toilet.